This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2002-173700, filed Jun. 14, 2002; and No. 2002-326304, filed Nov. 11, 2002, the entire contents of both of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a semiconductor device having an encapsulating layer for covering a distributing line and a method of fabricating the same.
2. Description of the Related Art
FIG. 36 shows an example of a semiconductor device called a CSP (Chip Size Package). This semiconductor device has a silicon substrate 104. A plurality of connecting pads 105 made of aluminum are formed on a peripheral portion of the upper surface of the silicon substrate 104. A silicon oxide insulating layer 106 is formed on the connecting pads 105 except for their central portions and on the upper surface of the silicon substrate 104, and a polyimide protective layer 108 is formed on the insulating layer 106. The central portions of the connecting pads 105 are exposed through holes 107 formed in the insulating layer 106 and protective layer 108.
Distributing lines 110 are formed from the upper surfaces of the connecting pads 105 exposed through the holes 107 to predetermined portions of the upper surface of the protective layer 108. Each distributing line 110 is made up of a metal undercoating 110a and an upper metal layer 110b which is formed on the upper surface of the metal undercoating 110a and made of copper. Columnar electrodes 111 made of copper are formed on the upper surfaces of pad portions at the ends of the distributing lines 110. On the upper surfaces of the protective layer 108 and the distributing lines 110, an encapsulating layer 117 made of an organic resin such as an epoxy-based resin is formed such that the upper surface of the encapsulating layer 117 is leveled with the upper surfaces of the columnar electrodes 111. Solder balls 119 are formed on the upper surfaces of the columnar electrodes 111.
In the above conventional semiconductor device, the encapsulating layer 117 is adhered to that upper surface of the protective layer 108, which is not covered with the distributing lines 110, to the surfaces of the distributing lines 110, and to the outer surfaces of the columnar electrodes 119. The above-mentioned conventional reference describes that the distributing lines 110 and columnar electrodes 111 are made of copper, and the encapsulating layer 117 is formed by an organic resin such as an epoxy-based resin. As will be described later, a pressure cooker test reveals that the adhesion between the encapsulating layer 117 made of an organic resin such as an epoxy-based resin and the copper distributing lines 110 and copper columnar electrodes 111 is not necessarily satisfactory. If the adhesion between the encapsulating layer 117 and the distributing lines 110 and columnar electrodes 111 is insufficient, the encapsulating layer 117 easily peels off from the surfaces of the distributing lines 110 and the outer surfaces of the columnar electrodes 111, resulting in an unsatisfactory encapsulating effect.
It is an object of the present invention to provide a semiconductor device and a method of fabricating the same by which the adhesion between an encapsulating layer and the surface of a distributing line and between the encapsulating layer and the outer surface of a columnar electrode increases.
According to an aspect of the present invention, there is provided a semiconductor device comprising
a semiconductor structure including a semiconductor substrate having an integrated circuit portion, and a plurality of connecting pads connected to the integrated circuit portion,
a plurality of distributing lines formed on the semiconductor structure, electrically connected to the connecting pads, and having connecting pad portions, and
an encapsulating layer made of a resin, and formed on the semiconductor structure and upper surfaces of the distributing lines,
wherein a copper oxide layer is formed on a surface of each of the distributing lines except for at least the connecting pad portions.
According to another aspect of the present invention, there is provided a fabrication method of a semiconductor device comprising
preparing a semiconductor structure including a semiconductor substrate having an integrated circuit portion, and a plurality of connecting pads connected to the integrated circuit portion,
forming, on the semiconductor structure, a plurality of distributing lines connected to the connecting pads and having connecting pad portions,
forming a copper oxide layer on a surface except for at least the connecting pad portions of the distributing lines, and
forming an encapsulating layer made of a resin on the semiconductor structure including upper surfaces of the distributing lines.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.